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Invention Publication
CN103664576A (甲基)丙烯酸的制备方法 无效 - 驳回

(甲基)丙烯酸的制备方法
Abstract:
本发明提供反复进行多次结晶操作从粗(甲基)丙烯酸得到精制(甲基)丙烯酸时，可简便地防止(甲基)丙烯酸的聚合的(甲基)丙烯酸的制备方法。本发明为通过反复进行n次从含(甲基)丙烯酸溶液得到(甲基)丙烯酸熔融液的结晶操作，从粗(甲基)丙烯酸制备精制(甲基)丙烯酸的(甲基)丙烯酸的制备方法，在第1次至第n-1次的结晶操作中得到的(甲基)丙烯酸熔融液、以及供给到第2次至第n次的结晶操作中的含(甲基)丙烯酸溶液中不添加聚合抑制剂，调整供给到第1次的结晶操作的结晶化工序中的含(甲基)丙烯酸溶液的聚合抑制剂浓度，使得供给到第n次的结晶操作中的含(甲基)丙烯酸溶液的聚合抑制剂浓度达到2质量ppm以上。
Abstract(English):

The present invention provides a process for producing (meth) acrylic acid, which can prevent the polymerization of the (meth) acrylic acid simply when many times of crystallization operation for obtaining a (meth) acrylic acid melt from a (meth) acrylic acid solution are carried out repeatedly to obtain the purified (meth) acrylic acid from crude (meth) acrylic acid. A polymerization inhibitor is not added to the (meth) acrylic acid melt obtained in the first to n-1th crystallization operation(s) and the (meth) acrylic acid solution subjected to the crystallizing step of the second to nth crystallization operation(s). The concentration of a polymerization inhibitor in the (meth) acrylic acid solution subjected to the crystallizing step of the first crystallization operation is adjusted, so that the concentration of the polymerization inhibitor in a (meth) acrylic acid solution subjected to the crystallizing step of the nth crystallization operation is 2 ppm by mass or higher.

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